Automatic switch-control circuits



S. B. WILLIAMS, 1n.

AUTOMATIC SWITCH CONTROL CIRCUITS.

APPLICATION FILED MAR. 1a. 1916.

1 3 1 2, 88 4 Patented Aug. 12, 1919.

/nven/or: Samuel B. VV/Y/I'dmsJ/r y W I i J r., a citizen of the United States, residing Switch-Control Circuits, of which the fol- STATES ATENT clarion.

sums]; 2B. wmmms; .13., or BROOKLYN, NEW YORK, nssrenon 'ro WESTERN mnc'rmc comrm, mconrommn, or NEW YORK, 1:. Y., A conronmrou or NEW .Yonx. 1

- I AUTOMATIC SWITCH-COR'TROL CIRCUITS.

Specification of Letters Patent. v Patented Aflg, 12, 1919,

Application meiumh 16,1916. SeriaINo. 814,580.

To all whom it may concern: x I

Be it known that I, SAMUELB. WILLIAMS,

at Brooklyn, in the county of Kingsand State of New York, have invented certain new and useful Improvements in Automatic lowingis a full, clear, concise, and exact description. a r

This invention relates to controll ng circuits for automatic switches suitable for use in telephone systems, and more particularly to control circuits for a switch, whose brush carrying mechanism is arranged to bestepped'in a plurality of directions.

The control circuits for such a switch include broadly, a line relay, a rotary stepping magnet, a vertical stepping magnet, and an escape magnet for operating a side switch.

In order to function properly this escape magnet must be slow to release under certaln conditions.

The object of the present invention is to provide a circuit arrangement by means of which the escape magnet may be made slow 'to release during certain operations. and

quick to release during certain other operations.

In this arrangement, the escape magnet has two windings, one of said windings having suflicient ampere turns toenergize the magnet when the other winding is shortcircuited. The resistance and turns of the two windings are so proportioned that when they are in series, their combined ampere turns are insuflicient to maintain the magnet energized. Its release, however, will be slow, duefto the fact that, as the second winding is cut in, it builds up a flux which tends to maintain the current in the first winding, and similarly, the change. of current in the first winding tends to set up a current in the second winding; the result of this mutual action being that a longer time is required for the ampere turns to be reduced to such an extent as to allow the release of the magnet than would be the cuit, since it may obviously be adapted for use with ,circu'itsfor other forms of auto- '13, 1906. The distinguishing feature of the present structure, however, is aside switch .whlch may, under certain conditions, be operated upon the energization of its escape magnet, and, under other conditions, be op- 'erated upon the deenergization of its escape magnet. This is made possible by the omission ofcertain teeth from the ratchet wheel which" controls the movement of the side switch wipers. A side switch of this nature is described in an application of Oscar F. Forsberg, Serial No. 6,302, filed February 5, 1915, issued as Patent No. 1,252,420, Jan. 8, 1918. The invention will be more fully understood from. the following detailed description.

The subscriber at substation 1, desiring to establish connection with subscriber at substation 2, removes his receiver from the switchhook, and obtains connection automatically,by any well-known means such as v a line finder switch indicated by the brushes 3, over an idle trunk to the selector whose circuits are shown in the drawing. Line relay 5 is energized over the following circuit from grounded battery, left hand winding of relay 5, side switch wiper 6, in first position, one side of calling line, substation 1, other side of calling line, side'switch wiper 7, right hand winding of relay 5, and contact 8 to ground. The energization of relay '5 completes a circuit forescape magnet 9, as follows: from grounded battery, through left hand winding of magnet 9, side switch wiper 10, front contact and armature of relay 5 to ground. At this time the right hand.

winding of magnet 9 is short-circuited, thereby allowing escape magnet 9 to pull up and move the side switch into its second position.

The calling subscriber now operates his impulse transmitter, thereby causing the successive attraction and release of the armature of line relay 5. At each release a circuit is completed from grounded battery,

side switch wiper 11, through rotary magnet 12, side switch wiper 13, back contact and armature of line relay 5 to ground. The escape magnet does not release while impulses are being sent, being energized over the following circuit when the armature of line relay 5 is on its back contact: from grounded battery, left hand winding of escape magnet, side switch Wiper 10, back contact and armature of rotary magnet 12, side switch wiper 13, back contact and armature of line relay 5 to ground. This circuit is broken each time the line relay attracts its armature, but the escape magnet does not release, its slow release circuit now being complete from grounded battery, through left and right hand windings of magnet 9 in series, front contact and armature of relay 5 to ground. The two windings of the escape magnet now being connected in series, the magnet is slow to release as heretofore described, and remains energized until it again receives an energizing impulse through its operating winding only, which takes place as soon as the line relay is deenergized. After the impulses have been sent, the line relay remains energized, and after a certain lapse of time the escape magnet releases, moving the side switch into its third position. v

In the third position of the side switch, the vertical magnet comes into operation and the switch automatically hunts for an idle trunk. As side switch wiper 16 moves into position 3, it closes the circuit of interrupter magnet 17 as follows: from grounded battery, through magnet 17, armature and back contact of vertical magnet 14, side switch w'iper 16, and thence to ground.

The pulling up of magnet 17 energizes vertical stepping magnet 14, the circuit being from ground, through armature and front contact of relay 17, contact 15, vertical stepping magnet 14, side switch wiper 11 to battery and ground. Stepping magnet 14 pulls up and in doing so breaks the circuit of interrupter magnet 17 at the back contact of said stepping magnet. The interrupter magnet 17 is therefore deenergized and in turn breaks the circuit of stepping magnet 14, the armature of which in falling back again completes the circuit of the interrupter magnet. In this way the circuit of the stepping magnet is alternately made and broken, until the test brush 18 of the selector finds a contact having connection to ground, at which time the escape magnet pulls u and moves the side switch into fourth position, the energizing circuit for the escape magnet being as follows: from grounded battery, through left hand winding of escape magnet 9, side switch wiper 10, side switch wiper 19, test brush 18 and thence to ground.

In case all of the trunks are busy, the contacts 15 and 8 will be opened after the tenth vertical step. The opening of contact 15 opens the circuit of the vertical stepping magnet and stops the switch. As contact 8 opens, contact 20 closes and puts a busy tone on the line. The circuit for producing this tone is from ground, through secondary windin of coil 22 (the primary winding of coil 22 being connected to a source of alternating current) right hand winding of relay 5, side switch wiper 7, one side of calling line, through substation 1, other side of calling line, side switch wiper 6, left hand winding of relay 5 to battery and ground. The calling subscriber on hearing the busy signal restores his receiver to the sWitchhook, thereby opening the circuit of line relay 5, the armature of which then falls back, thereby closing circuit from ground, through armature and back contact of relay 5., side switch wiper 13, rotary off-normal contact 24, release magnet 23 to battery and ground. Release magnet 23 pulls up, and remains locked up by means of its left armature and front contact until the off normal contact 24 is opened by the return of the switch to normal position.

Should the calling subscriber decide to abandon a call and restore his receiver to the switchhook while impulses are still being sent, the line relay 5 will at once be deenergized, maintaining the circuit of the rotary stepping magnet 12 through the back contact and armature of said relay 5. Magnet 12 will therefore hold its armature attracted, and it will be seen that at this time the circuits of both windings of escape mag net 9 are open. Magnet 9 is then able to release quickly, its action'being the same as that of a magnet having a simple winding, and moves the side switch into position 3, whereupon the entire mechanism is restored to normal over the circuits previously described for the condition in which all the trunks are busy.

We will assume, however, that neither of the above mentioned conditions existed, and

that the side switch moved into its fourth position, thereby establishing connection through to an outgoing trunk. As soon as the idle trunk is seized, ground is removed from the test contact 25 by the switch next to act, which may be either a connector or another selector. The connection from this point may be completed in any well-knownmanner.

At the conclusion of the conversation the connection is released when ground is again put on contact 25 by the'switch immediately following the switch whose operation is being described. A circuit for release magnet 23 is then formed from grounded battery, through release magnet 23, contact and armature of escape magnet 9, side switch wiper 19, brush 18, contact 25 and thence to ground. Release magnet 23 then pulls up and remains locked up as previously described.

At the right hand contact and armature of magnet 23 is shown a well-known device 26 to reduce sparking at the various contact points associated with the selector. This de vice comprises a grounded battery, a resistance and a condenser.

lVhat is claimed is:

1. In a telephone exchange system, a controlling switch, wipers and an escape magnet for said controlling switch, a pluralit of windings for said magnet, a circuit inc uding part of said windin s for energizing said magnet, and a circuit lncluding said windings in series for making said magnet 'slow to release, the first named circuit being controlled by a wiper of said controlling switch.

2. In a telephone exchange system, a controlling switch, an escape magnet for operating said switch, a plurality of windings for said magnet, and means for making said magnet either fast or slow to release, said means being arranged to maintain the windings connected in series to make said magnet slow to release and to open the circuit of all the windings to make said magnet quick to release.

3. In a telephone exchange system, a controlling switch, wipers for said controlling switch, an escape magnet for operatin said switch, an energizing winding there or, a second winding for said magnet, and means, including said wipers, for short-circuiting the second winding to allow the magnet to pull up, said means being arranged either to connect the windings in series to make said magnet slow to release, or to open the circuit of both windings to make the magnet quick to release.

4. In a telephone exchange system, an automatic switch, electromagnets for controlling the setting and restoration of said switch, a controlling electromagnet for governing the operation of said electromagnets, said controlling electromagnet being provided with two windings, means for completing a circuit through one onl of said windings to energize said controlling electromagnet, and means for completing a circuit through said windings in series to make paid controlling electromagnet slow to recase.

5. In a telephone exchange system, an automatic switch, electromagnets for controlling the settin and restoration of said switch, a contro ling electromagnet for governing the operation of said electromagnets, said controlling electromagnet being provided with two windings, means for completing a circuit through one of said windings to energize said controlling electromagnet, means for completing a circuit through said windings in series to make said controlling electromagnet slow to release, and means to open the circuit of both windings to make said controlling electromagnet quick to release.

6. In a telephone exchange system, an automatic switch, electromagnets for controlling the setting and rest-oration of said switch, a controlling electromagnet for governing the operation of said electromagnets, said controlling electromagnet being provided With a plurality of windings, a circuit including said windings in series, means for short-circuiting certain of said windings to render the remainder of said windin s operative, means for opening said short circuit to render the controlling electromagnet slow to release, and means for opening the circuit of all of the windings to render the controlling electromagnet quick to release.

7. In a telephone exchange system, an automatic switch, electromagnets for controlling the setting and restoration of said switch, a controlling electromagnet for governing the operation of said electromagnets, said controlling electromagnet being provided with an energizing winding and a second winding, an energizing circuit including said energizing winding, means for completing said circuit to energize said controlling electromagnet, a series circuit for said windings, and means for completing said series circuit, whereby the controlling electromagnet is made slow to release.

8. In a telephone exchange system, an automatic switch, electromagnets for controlling the setting and restoration of said switch, a controlling electromagnet for governing the operation of said electromagnets, said controlling electromagnet being provided with an energizing winding and a second winding, an energizing circuit including said energizing winding, a series circuit for said windings, whereby the controlling electromagnet is made slow to re lease, and a movable contact for alternately completing said energizing circuit and said series circuit.

In witness whereof, I hereunto subscribe my name this 11th day of March A. D., 1916.

SAMUEL B. WILLIAMS, JR. 

